1. Field of the Invention
This application is directed to an umbrella that has a canopy suspended from an extendable support member. In particular, this application is directed to an umbrella that includes extension and deployment mechanisms that can be driven by a crank handle.
2. Description of the Related Art
Umbrellas have been developed to provide shelter from the elements and are particularly useful in outdoor seating areas, such as on a backyard patio. Typically, an umbrella comprises a support pole and a canopy positioned at the top of the pole for providing shade. Basic umbrellas have the support pole centrally located directly beneath the canopy. This construction has several disadvantages. For example, the pole is located at the most sheltered position under the canopy. Also, the pole obstructs the view of persons seated beneath the canopy. Some umbrella designs locate the support pole to the side of the canopy, generally suspending the canopy from above. A disadvantage of these designs is that they take up more space than umbrellas supported from below. A few umbrella designs support a canopy from above and are retractable to reduce the amount of space that they require.
For example, U.S. Patent Application Publication No. 2004/0055628 A1 describes an umbrella that includes upper and lower support rods, ribs, a panel supported by the ribs, and a hand cranking device. The upper rod is located within the lower rod of the retractable device. The hand cranking device is located within a lower portion of the lower support rod. The hand cranking device includes a drive worm gear connected to a handle. Separate driven worm gears are positioned on two sides of the drive worm gear. The driven worm gears separately connect to rotating wheels. Each of the wheels has a rope entwined upon it. One rope is coupled with the ribs and thereby with the panel. The other rope is coupled with the upper support rod. The umbrella is arranged so that the upper rod is extended from the lower rod and the panel is deployed by turning the handle. More particularly, the umbrella is arranged so that turning the handle simultaneously extends the upper rod and then deploys the panel. Reverse operation of the hand crank closes the panel and then retracts the upper rod.
This arrangement is disadvantageous in several respects. For example, the upper support rod apparently has to be fully extended from the lower support rod in order for the ribs and panel to be expanded. This greatly limits the positionability of the umbrella. In particular, this arrangement requires the entire umbrella to be repositioned for changes in position of the sun. Additionally, impairment of one of the extension function and the deployment function will render the umbrella inoperable.
Another design that is commercially available comprises upper and lower support rods, a handle to deploy a canopy, and a locking screw. In this device, the upper and lower support rods are side-by-side and are joined by a figure-8 shaped block. The block includes a tightening screw that clamps the upper support rod to the lower support rod. The canopy is raised by loosening the screw and pushing the upper support rod by hand to a higher elevation. To maintain the upper support rod at the higher elevation, the tightening screw is tightened. This umbrella design has several disadvantages. For example, it can only be raised and lowered by hand. As such, the height to which the canopy can be raised is limited by the height of the user. Additionally, the size and choice of materials for the umbrella are limited by the requirement that the assembly be light enough to be lifted by a user. Thus, this design inherently limits the range of possible applications and uses. Additionally, the block slides along the lower support rod and could damage or disfigure the outer surface thereof.